Cigarette filter

ABSTRACT

Two-part cigarette filter for insertion into the end of a cigarette. A first body has an axial aperture substantially in the form of a venturi and which has a circular groove downstream face, and a second body downstream of the first body defines a recessed chamber in its upstream face having a wall opposite the aperture presenting an impingement surface for smoke passing through the aperture. The second body has spaced projections circumferentially arranged and located outwardly of said surface which extend into and engage the groove. Radial apertures extend outwardly from the chamber between the projections and between the faces and longitudinal channels extending along the periphery of the second body. The radial apertures are disposed in the path of flow of smoke upstream of the impingement surface compelling reversal of the flow of smoke prior to entering the radial apertures and the longitudinal channels.

United States Patent [72] lnventors Tonino Virgili Via F. lli Cairoli 27; Giancarlo Capotondo, Via Oberdan 30, both of Castelfidardo, Ancona, Italy [21] Appl. No. 793,390 [22] Filed Jan. 23, 1969 [45] Patented Jan. 26, 1971 [32] Priority Oct. 23, 1968 331 ltaly 231 A/68 [S4] CIGARETTE FILTER 2 Claims, 2 Drawing Figs.

[52} US. Cl 131/261, 131/210,131/201 [51] Int. Cl A24d 01/04, A24f 07/04, A24f 13/06 [50] Field of Search ..13 1/261 (B),

[56] References Cited UNITED STATES PATENTS 3,269,394 8/1966 Curtix, Jr (131/10.5UX) 3,312,227 4/1967 Barnett l31/261(B)UX) Primary Examiner-Samuel Koren Assistant Examiner-James H. Czerwonky Attorney-Robert H. Jacob ABSTRACT: Two-part cigarette filter for insertion into the end of a cigarette. A first body has an axial aperture substantially in the form of a venturi and which has a circular groove within its downstream face. and a second body downstream of the first body defines a recessed chamber in its upstream face having a wall opposite the aperture presenting an impingement surface for smoke passing through the aperture. The second body has spaced projections circumferentially arranged and located outwardly of said surface which extend into and engage the groove. Radial apertures extend outwardly from the chamber between the projections and between the faces and longitudinal channels extend along the periphery of the second body. The radial apertures are disposed in the path of flow of smoke upstream of the impingement surface compelling reversal of the flow of smoke prior to entering the radial apertures and the longitudinal channels.

CIGARETTE FILTER The present invention relates to cigarette filters.

More particularly the cigarette filter according to the invention comprises a body adapted to be applied to a cigarette, having at least one axial aperture, substantially in the form of a venturi and opening into a chamber and having one wall providing a stop member for the smoke which passes through the aperture. This chamber is in communication with the area downstream from the stop member through radial apertures provided in the body and longitudinal passages in the outer wall of the body.

With this arrangement of the filter the smoke, being compelled to pass during the inhalation of the smoker, through the axial hole in the fonn of a venturi, is accelerated to high speed and undergoes a sudden fall in temperature. At this speed and temperature the smoke impinges violently against the surface of the chamber forming the stop member and leaves a large amount of its tar contents condensed on this wall. Purified in this way the smoke continues its path up to the smokers mouth through the apertures and passages in the body.

The invention will be better understood from the following detailed description, given merely by way of example and therefore in no limiting sense, of an embodiment of the invention illustrated in the accompanying drawings, in which:

FIG. 1 is an axial section of the filter according to the invention; and

FIG. 2 is an exploded view in perspective, of the filter in FIG. 1.

Referring to these FIGS. it may be seen that the filter defines a capsule in two parts, referred to respectively as A and B. The part A is in the form of a disc traversed axially by an aperture having substantially the form of a venturi with a highly flared inlet surface P. The part B also has the form of a disc with a cavity or chamber C whose bottom wall or surface is shown at S. Extending from one side of the disc are three projections N whose cross sections are in the form of segments of a circle, adapted to engage, when the parts A and B are in an assembled condition, a suitable circular groove M provided on one side of the part A. Transverse apertures L are thus provided which extend outwardly from the chamber C and communicate with longitudinal passages H in the periphery of the part B.

Once the two parts are joined together as shown in FIG. 1, the nature of the plastic material from which they are made and the cigarette paper around them holds them together. The capsule is applied to the cigarette, preferably inside the latter, in the place where the filter usually'is, if any. The diameter of the capsule will be chosen in such a way as to correspond substantially to the inner diameter of the paper wrapping of the cigarette.

The operation of the filter described, based on the aerodynamic principle of the venturi, is as follows:

The smoke, being compelled to pass during the inhalation by the smoker, through the hole 0 accelerates to high speed and undergoes an abrupt drop in temperature. At this speed and temperature the smoke impinges violently against the surface S of the chamber C and leaves a large amount of its tar contents condensed on the surface S. Purified in this way, the smoke continues its path up to the mouth of the smoker passing through the apertures L and the passages H.

The capsule described therefore permits the smoker to inhale the smoke produced by the combustion of the tobacco, already free to a large extent, from a high amount of the notoriously harmful tarry products.

The capsule is preferably made of plastics material, but it can also be made of other material.

There can be more than one hold 0 and thus likewise the number of the chambers C, of the apertures L and of the channels H can be any number whatsoever. Moreover the capsule can be made in any number of pieces, if necessary even in a single piece.

Generally, although only one embodiment of the invention has been illustrated and described, it is obvious that a number of changes and modifications can be made without departing from the scope of the invention.

1 claim:

1. A filter for insertion into the end of a cigarette, made of two axially spaced and aligned disclike parts having the same maximum diameter, one of said parts comprising a first body defining an axial aperture substantially in the form of a venturi and also having an internal circular groove within its downstream face, the other of said parts comprising a second body downstream of said first body and having its upstream face including a recessed chamber therein opposite said aperture, said chamber defining an impingement surface at its downstream end for smoke passing through said aperture, said upstream face having spaced projections circumferentially arranged and located outwardly of said surface and extending upstream, said projections extending into and engaging the surfaces of said groove, radial apertures extending outwardly from said chamber between said projections and between said faces and longitudinal channels extending along the periphery of said second body, said radial apertures being disposed in the path of flow of smoke upstream of said surface, compelling reversal of the flow of smoke prior to entering said radial apertures and said longitudinal channels.

2. A filter as claimed in claim 1 where the projections are of greater length than the depth of said groove so as to define said outwardly extending apertures. 

2. A filter as claimed in claim 1 where the projections are of greater length than the depth of said groove so as to define said outwardly extending apertures. 